1. Field of the Invention
This invention relates to a door closing device, and more particularly to a door closing device that can retain a door at a desired open position and that can close the door automatically.
2. Description of the Related Art
Referring to FIG. 1, a conventional door closing device is shown to include a cylinder 11 having one end connected to a door frame (not shown) of a door (not shown), a piston rod 12 having one end extending out of the cylinder 11 and connected to the door, and a latch 13 movably sleeved on the piston rod 12. A restoring force is stored inside the cylinder 11 for automatic closing of the door. To position the door at a desired opening angle, the latch 13 is pushed to abut a lower portion thereof against an end periphery of the cylinder 11 so that a portion of the piston rod 12 which is pulled out of the cylinder 11 can engage a hole in the latch 13, thereby retaining the door at the desired opening angle. To close the door, a force is exerted on the door and the latch 13 is pushed to move the lower portion thereof away from the end periphery of the cylinder 11. Through the restoring force stored inside the cylinder 11, the door can close automatically. However, the latch 13 deviates easily and cannot accurately retain the door at the desired open position. Further, because the latch 13 is exposed, injury to the user's hand easily occurs.
Referring to FIG. 2, another conventional door closing device is shown to include a cylinder 21 having one end connected to a doorframe (not shown) of a door (not shown), a piston rod 22 having one end extending through the cylinder 21 and connected to the door, a latch 23 sleeved on the piston rod 22, a lever 24 connected to the latch 23, and a restoring spring 25 abutting between an end periphery of the cylinder 21 and the latch 23. A restoring force is stored inside the cylinder 21 for automatic closing of the door. To position the door at a desired opening angle, one of the user's hands pushes the door to an opening angle, while the other hand of the user pushes the lever 24 so that the latch 23 engages the piston rod 22, thereby retaining the door at the desired opening angle. To close the door, a force is exerted on the door, and, through the restoring spring 25 and the restoring force in the cylinder 21, the door closes automatically. However, both hands of the user are required to open the door, so that the conventional door closing device is inconvenient to use.